1. Field of the Invention
The present invention relates generally to communication devices, and more particularly, to such a device capable of operating in conjunction with a free-running oscillator.
2. Related Art
A known communication system includes a basestation transmitter/receiver (referred to as a transceiver) and one or more subscriber transceivers remote from the basestation. The basestation transceiver transmits a downstream communication signal including useful information (such as audio, video, etc.) to the subscriber transceivers. Each subscriber transceiver includes a receiver to recover the useful information from the downstream signal. Typically, the receiver first recovers/extracts inherent timing and/or frequency information from the downstream signal, for example, by frequency synchronizing an oscillator in the receiver to the downstream signal. Then, the receiver uses the recovered timing and/or frequency information to recover the useful information conveyed by the downstream signal.
Similarly, the basestation may also need to be able to recover inherent timing and/or frequency information from the upstream signal transmitted by the subscriber transceiver. However, some basestations may be incapable of recovering such upstream timing and/or frequency information unless it is closely matched to the downstream frequency and/or timing information.
It is desirable to keep the subscriber transceiver complexity, and thus overall cost, as low as possible. One cost driver in the subscriber transceiver tends to be any high frequency oscillator for generating high frequency signals used in or in conjunction with the transceiver. For example, oscillators used to generate signals in the GigaHertz (GHz) frequency range tend to be expensive, and thus, drive-up the overall cost of the transceiver.
Therefore, there is a need for a transceiver capable of extracting timing and/or frequency information from a downstream signal.
There is a further need for a transceiver capable of generating an upstream signal including inherent frequency and/or timing information that is closely matched to the frequency and/or timing characteristics of a downstream signal received by the transceiver.
There is an even further need for a low cost transceiver. There is a related need to reduce the cost of a high frequency oscillator used in or in conjunction with the transceiver, as compared to known systems.